Effects of personal control over hospital noise on sleep

Abstract

Critical Care Unit (CCU) sound levels, subjective stress due to noise, and sleep were studied in 105 female volunteers in a simulated hospital environment. Subjects were randomly assigned to instruction in personal control over noise via the availability of a sound conditioner, no instruction in personal control over noise, or quiet conditions. Subjects in the two noise conditions heard audiotape-recorded CCU nighttime sounds while attempting to sleep overnight in the laboratory. The intervention did not facilitate better sleep as measured by polysomnograph equipment and self-report. However, the results provided strong support for a causal relationship between CCU sounds and poorer sleep. When compared to the quiet condition, subjects in the noise conditions had poorer sleep efficiency; more difficulty falling and staying asleep; more difficulty progressing from one stage of sleep to the next; more intrasleep awakenings; spent less time in Rapid Eye Movement sleep; and poorer sleep via self-report (all ps < 0.03). As predicted, scores for subjective stress due to CCU sounds yielded significant relationships with 9 of 16 measures of sleep (all ps p p p <0.001) of the variance in Rapid Eye Movement sleep was accounted for by CCU sound levels.